A Maryland research center established to protect soldiers from chemical and biological attack has been enlisted in the fight to save honeybees from the mysterious disorder that has been devastating commercial bee populations.
Scientists at the Edgewood Chemical Biological Center, at the U.S. Army's Aberdeen Proving Ground in Harford County, have turned equipment developed several years ago to identify proteins present in potential biological weapons, such as anthrax, to figure out what kind of viruses, bacteria or other pathogens are killing the bees.
"It's a biological detector that helps us identify threats on the battlefield," said Don Kennedy, communications officer for the center. "What we did was apply this technology in a different way."
The collaboration between the Army and bee scientists was described this week in a scientific paper published in the online journal
.
The researchers, led by Jerry J. Bromenshenk at the University of Montana, said they found a previously unsuspected virus and a parasitic fungus that appear to work together to cause the "colony collapse disorder."
The mysterious disease has cost commercial bee keepers as much as 90 percent of their bees in die-offs in recent years. The bees play a critical role in the nation's agricultural productivity. The U.S. Department of Agriculture says a third of the nation's diet depends on insect pollination.
"We felt a lot better about our technology, and felt like we'd been of service to the people who asked us for help," said Charles H. Wick, a microbiologist at the Edgewood center. "It would be wonderful to help move a solution to [colony collapse disorder] forward."
Not everyone is persuaded by the new paper.
"It's wonderful to try new tools, new techniques for identifying pathogens," said Jay Evans, a research geneticist working in the bee research lab at the USDA's Agricultural Research Service in Beltsville.
"But for this [virus] to really be something that missed scrutiny for several years of really intense searching, it needs a high burden of proof. And we're all scratching our heads as to where this faith is coming from. It doesn't come out from the paper itself."
Wick responded: "The journals never let you publish all the data. We have lots of data. I have lists of all the peptides [proteins] in all the samples." And they should be enough to persuade skeptics, he said.
Has the work solved the mystery? "No," Wick said. "But we've definitely pointed the direction for further research. It opens a whole new chapter for looking into honeybee health care."
Scientists will now have to verify the findings and begin looking for ways to disrupt the pathogens or keep them from infecting the bees.
Colony collapse disorder, or CCD, began to get worldwide attention in 2007, after commercial beekeepers in the U.S. reported winter losses of 30 percent to 90 percent of their colonies.
Colony collapses, or "dwindles," were not new to beekeepers. But this one seemed to be more serious, both in the number of abandoned hives and in their coast-to-coast geography.
Losses since 2007 have diminished somewhat, Evans said, but still account for a quarter of wintertime losses, or 6 percent of the hives. And the disorder can still claim 90 percent of some commercial colonies.
Curiously, the bees don't just sicken and die. They disappear, apparently flying off to die elsewhere.
Previous studies found a variety of possible suspects, among them the Varroa Destructor-1 virus and Israeli acute paralytic virus.
In the PLoS ONE paper, Bromenshenk and his team reported finding another pathogen, one that appears to be tightly linked to the collapsed colonies.
The viral detection work at the Edgewood center used a technology called Integrated Virus Detection System/ Proteomic Mass Spectrometry. Developed for the battlefield detection of viruses, it can quickly identify the presence of protein fragments unique to specific pathogens.
Kennedy said the Montana team contacted the center after Bromenshenk was tipped off about the center's capabilities by Wick's brother, who lives in Montana.
"We collaborate with a lot of different agencies," Kennedy said. "We've worked with the USDA. We've worked with the Postal Service putting in biological detectors in mail sorting machines. And every now and then there's an instance that comes up in which the technology can be applied in a different way."
Wick said, "We never thought about bees as being a sample. … This wasn't even on our radar."
But it became an opportunity to "field-test" the technology. "We ground up the bees, put them through the system and out popped the viruses, and the fungi and a whole bunch of bacteria."
The Edgewood center soon discovered that a virus belonging to a class called
Irioviridae
, or invertebrate iridescent virus, when it occurred together with a parasitic gut fungus called
Nosema ceranae,
correlated with the collapse disorder to a very high level of statistical certainty.
"They occurred together in all the hives that collapsed that we examined," Wick said. The virus seems to be absent in healthy colonies, and increases in prevalence as colonies fail and collapse.
What's more, the researchers reported, laboratory trials with the two pathogens "confirmed that co-infection with these two pathogens was more lethal to bees than either pathogen alone."
That would fit with Evans' notion that the parasitic fungus provides an opening in the bees' gut through which viruses in the bees' gut can infect and sicken the insects. Such two-pronged attacks have been reported before in other insects.
But he's not yet persuaded that the
Irioviridae
virus is the right — or even the only — viral culprit.
The
Iridoviridae
virus belongs to a relatively small group known in caterpillars and mosquitoes, and has been used as a viral control agent against pest species of moths, he said.
But in bees, Evans said, "I'm confident we don't have any virus close to this described one. … I'm puzzled that it seemed to be pretty widespread in their bees."
"Hopefully," he said, more data from the research "will emerge in the next few months. It's not super-convincing right now."
That said, Evans welcomed the participation of people from outside entomology and agriculture labs. "I don't know of any other Army labs getting involved in the bee world," he said.
The search for the cause of CCD has spotlighted a succession of potential pathogens in recent years. The Edgewood technology was used in 2007 to identify the
Nosema ceranae
fungus as an abundant presence in bees from collapsed hives.
Later that year, scientists from Penn State University, the USDA, the National Institutes of Health and elsewhere joined forces to conduct a "metegenomic survey" to sequence all the genes from affected bees, including all the bacteria, viruses, fungi and other pathogens in their bodies.
That work pointed to the Israeli acute paralytic virus, which had been found in bee colonies imported from Australia, and in royal jelly imported from China for human consumption and cosmetics.
In 2008, the Edgewood center and scientists at the University of Montana detected the Varroa Destructor Virus-1 as another suspect in colony collapse disorder. It was the first detection of the virus in U.S. honey bees.
Situated on the neck of land between the Gunpowder and Bush Rivers in Harford County, the Edgewood Area, formerly the Edgewood Arsenal, has been defending the nation against chemical and biological threats since World War I. Its research and development work has ranged from battlefield gas masks to waste-to-energy systems that convert garbage at U.S. bases in Iraq to electricity.
In 1920, all of the U.S. Army's chemical warfare functions, including training and research, were transferred to the growing facility.
Edgewood personnel helped to develop portable chemical analysis labs for battlefield use in 1929, according to an online base history. That was followed by decontamination agents, mustard gas and nerve gas detectors.
During the first Persian Gulf War, Edgewood researchers developed mobile detection systems to provide Desert Storm troops with early warning of radiological, biological and chemical agents. Newer, more sophisticated versions have followed.
In 1996, Congress designated the Edgewood Chemical Biological Center (ECBC) as the lead agency for domestic preparedness. It provides federal, state and local emergency responders with training and equipment to enhance their response to the potential use of chemical, biological or radiological weapons.
The bee research in the PLoS paper was funded by U.S. Defense Department, the Montana Agricultural Research Station, the National Honey Board, the California Almond Board, California Beekeepers Association and the Foundation for the Preservation of the Honeybee.
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What is colony collapse disorder?
Origins:
Beekeepers first noted major losses in October 2006
Symptoms:
Adult honeybees disappear from hives, leaving food and often a queen and immature brood, but no dead adults.
Cause:
Undetermined. Stress, pesticides or other toxins, and even cell phone towers have been suggested. But investigators are increasingly focusing on viral and fungal pathogens.
Casualties:
Some beekeepers report losses of 30 percent to 90 percent of their colonies. Last winter a quarter of all winter losses, or about 6 percent of the nation's bee colonies, were attributed to CCD.
At risk
: Bees are vital to pollination of food crops, especially nuts, fruits, vegetables and berries, adding $15 billion in value.
Source: USDA
Earlier versions of this article incorrectly reported that the Edgewood Chemical Biological Center is located at the Edgewood Arsenal. The arsenal was merged with the Army's Aberdeen Proving Ground in 1971. It is now known formally as the Edgewood Area of the Aberdeen Proving Ground.